There are some conventional sheet cassettes wherein sheet feeding is performed to a recording unit of a recording apparatus while bringing the uppermost one of recording media stacked on a pressing plate into pressure contact with a sheet feeding roller. Of such sheet cassettes, some are configured such that the recording media are spaced apart from the sheet feeding roller by pressing down the pressing plate by a given amount against a press-contacting force during a sheet feeding operation (see Japanese Patent No. 4006432).
Further, there are some sheet cassettes which have an elevation mechanism for moving a pressing plate toward a sheet feeding roller by generating an urging force in the process of mounting the sheet cassette into a main body. The elevation mechanism includes the pressing plate rotatably provided within the sheet cassette, a spring operably coupled to a free end of the pressing plate, and an elevating arm for pulling up the other end of the spring. In the main body, a guide for guiding the elevating arm is formed. In the process of mounting the sheet cassette into the main body, the guide pulls up the elevating arm, and the spring operably coupled to the elevating arm pulls up the pressing plate (see Japanese Patent Application Laid-Open No. 2002-154670).
Moreover, a mechanism for providing an opening for inserting paper sheets in the vicinity of a mounting port of the sheet cassette and feeding the sheets inserted into the opening using a separation/feeding mechanism of the sheet cassette is discussed in Japanese Patent Application Laid-Open No. 2004-269124. In this mechanism, a leading edge of the sheet inserted from the opening portion is guided toward a clearance between the sheets stacked in the sheet cassette and the sheet feeding roller.
However, in the sheet cassette discussed in Patent No. 4006432, the pressing plate is released by a given amount during a feeding operation, but there is no description whether the uppermost sheet of the recording media on the pressing plate is spaced apart from the sheet feeding roller at the time when mounting of the sheet cassette is completed. In addition, in the feeding apparatus discussed in Japanese Patent Application Laid-Open No. 2002-154670, there is a problem in that, because the recording medium on the pressing plate comes into press-contact with the sheet feeding roller at the time when mounting of the sheet cassette is completed, it is difficult to arrange a manual feed unit for manual sheet feeding on the top of the pressing plate using the same sheet feeding roller.
In the sheet feeding apparatus discussed in Japanese Patent Application Laid-Open No. 2004-269124, the manual feed unit for performing manual sheet feeding is arranged on the top of the pressing plate using the same sheet feeding roller, and the pressing plate is spaced apart from the sheet feeding roller by full-stroke. In the feeding apparatus discussed in Japanese Patent Application Laid-Open No. 2004-269124, however, a driving load becomes large in order to deal with a large capacity sheet feeding, because the pressing plate is spaced apart from the sheet feeding roller by full-stroke against press-contacting force necessary for sheet feeding.